Title

Author

Defense Date

2009

Document Type

Thesis

Degree Name

Master of Science

Department

Biology

First Advisor

Paul Bukaveckas

Abstract

I investigated seasonal and inter-site variation in factors influencing diel dissolved oxygen (DO) metabolism at four streams in the Virginia Coastal Plain. Data were collected monthly from January to August 2008 to characterize DO metabolism (diel DO amplitude, production, respiration), incident solar radiation (PAR), dissolved nutrients, fine benthic materials (mass, C:N, Chlα) and hydrology (discharge, water transit time, transient storage). Reach-scale metabolism estimates were determined using the one-station diurnal DO technique and transit time and transient storage were determined by conservative tracer additions. Incident solar radiation was the primary determinant of DO metabolism as streams experiencing higher light levels (Herring and Powell Creeks) exhibited greater diel DO amplitudes, production and respiration. Streams with greater riparian shading (Courthouse and Crump Creeks) exhibited lower DO metabolism despite their higher nutrient concentrations. Higher incident solar radiation was associated with greater benthic algal biomass at some (Herring, Crump, and Courthouse Creeks) but not all (Powell Creek) sites. Diel DO amplitudes were significantly and positively correlated with benthic Chlα and incident solar radiation at less shaded sites. These factors were not significant predictors of DO amplitude, production or respiration at more shaded sites.